Fuse mechanism for projectiles.



E. GATHMANN.

FUSE MECHANISM FOR PROJECTILES.

j APPLICATION FILED SEPT. 7. |911. 1,296,070.

2 SHEETS-SHEET l.

Patented Mar. L1,1919.

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E. GATHMANN.

FUSE MECHANISM FOR PROJECTILES.

- APPLICATION FILED SEPT. 7, ISII. 1 ,296,070. Patented Mar. 4, 1919.

2 SHEETS-SHEET 2 EMIL GATHMANN, OF BALTIMORE, MARYLAND.

FUSE MECHANISM FOR PROJECTILES.

Specification of Letters Patent.

Patented Mar. 4,1919.

Application led September 7, 1917. Serial No. 190,219.

To all whom it may concern:

Be it known that I, EMIL GATHMANN, a citizen of the United States, residing at Baltimore, in the State of Maryland, have invented certain new and 'useful Improvements in Fuse Mechanism for Projectiles; and I do hereby declare the following to be a full, clear, and exact description of the same, reference bein panying drawings, specification.

In the fuse mechanism commonly employed in connection with projectiles designed to be fragmented by an internal bursting charge, provision is made whereby a time train or fuse will be lighted during the initial movement of the projectile under the influence of the propelling charge, and -1 the length of the fuse'or train-determines the period-of time intervening between the discharge of the kprojectile and the time when the bursting charge is ignited. Ordinarily, the time train is ignited while the projectile is well within the bore of the gun, the common arrangement being a percussion primer or detonator which is red by an inertia member which tends to remain stationary, while the rojectile and the body of the fuse move fibrwardly with relation thereto with the result that the primer or n -detonator Vis exploded during the acceleration movement of the projectile. This arrangement has developed irregularities in action and produced conditions'whioh under some circumstances have caused premature explosion. The irregularity in action is .thought to be largely due to the fact that the projectile in moving forwardly in thel bore of the gun necessarily compresses and expels the volume of air in the gun bore and the longer the gun, the greater the compression and volume of -air necessarily expelled. The time or fuse train burns more rapidl under increased air pressure, and inasmuc as the air pressure has direct access to the time train there may be as much as two or three seconds difference in the rate of burning, although the time interval may be as llttle las 100 each inch of barometer pressure or each half pound pressure of the, air increases the rate j 'had to the accom. frming part` of thisv 2- of a second. Roughly speaking, I

pressure surrounding the fuse, while in the bore of the gun, may be as high as 100 pounds per square inch, it will be readily appreciated that the error or unequal burning will be a marked factor for which em-v pirical adjustment must be made. Tests indieate that .the error found to exist when a projectile is fired from along gun is as much as ten times that which occurswhen the projectile is fired from a shortor eld gun.

The object of the presentinvention is to overcome the errors pointed out and to provide Va detonator mechanism which will` ignite the time train at a time when it is not subjected to the air pressure within the boreof the gun, but, on the contrary, when it has actually begun its Hight from the muzzle of the gun.v In the preferred arrangement, provision is made whereby the detonator will be exploded immedlately after the projectile has received its maximum acceleration or has acquired its greatest velocity, this usually occurrin at from 10 to 30 feet from the muzzle of t e gun.

Other objects of the present invention are to provide 'a fuse mechanism embodying an inertia member and a firing member relatively movable in opposite directions for arming the fuse and movable in the same direction for firing, with locking mechanism intermediate the inertia and firing members "for retaining them in their relative positions for safety or for firing as the case may be whereby firing may be eii'ected subsequent tpl the maximum acceleration of the project. e.

j In the accompanying drawings Figure l is a-section in a plane longitudinally of the axis of a fuseV embodying the present invention with the parts in their normal or safety ositions.

Fig. 2 is a simi ar view with the parts in with -the parts in 'is a body portion A which is usually made `of brass and is adapted to be secured by a screw-thread connection-inthe nose portion Iof the projectile in a housing, which housing is in turn secured in the nose portion yof the projectile. A forwardly extending stem-like ortion A" of,the fuse body A serves as t e support for one or more rings or annular bodies -B, vB', and a cap or nut C which is threaded on the end of the stem and retains the rings in p osition. The cap C and stem itself are formed with an internal chamber preferably of cylindrical formation, for the reception of the firing mechanism of the detonator to be presently,y

described. The rings B, B are provided with internal passages in which the time tram or fuse composition D, D is located,

and one of the rings is usually made adjustable about they stem for setting the.' length of the time train, whereby the period during which the train will burn may be set at any point from zero to thefull length of the train and time for which it is designed. This construction is well known vandv 1s preferably in accord with so-called standard ractice. To permit fumes to escape. during'the combustion of the time train, the fuse mechanism is provided with l vent 'openings E usuall located in the cap pieceC and having their external ports bev neath an overhanglng part or flange c forma part of said cap.

in i

In the simple embodiment of the inven'y tion illustrated in the drawings the cap 'or 'detonator for igniting the time train or the magazine charge 1f no time train is employed, is mounted in fixed position and a movable firing pin is adapted to coperate 'therewlth to efl'ect detonation but in accord with well known andusual practice thisl arrangement may be reversed, the pin`being .statlonary and the cap or detonator'movable. As shown the cap or detonator F is mounted in the bottom of a,y capsule formed" in two parts G and G for' convenience in manufacture and charging and the capsule is held in the forward end ofthe body A preferably by a screw thread connection as Shown.

' In the rear of the capsule G the body of the fuse is formed With an axial chamber for the reception ofl the movable members l'fuse is unarm efectlve save a of the firing mechanism which members are preferabl inserted from the rear end of the cham er and retained by a closure cap orscrew plug y A Ihe Inova lemembers referred to comprlsezan inertla member` I and a firing mem up during the discharge of the projectile from the gun but adapted to permit of relative movement when subjected to such forces. When the relative movement takes place then the locking device locks the members together to yact as a unit in firing the detonator or cap.

The inertia member I is conveniently made in two parts I and I to form a chamber for the reception of a split ring i of such diameter as to normally project or overhang into the central bore of the mem` ber and in position to 'coperate with the 'inclined shoulder k on the firing member K. The body of the firing member is preferably cylindrical and providedwith a groove le for the reception of the split ring whenl relative movement of the members has taken place to lock them together and with a shoulder K2 for arresting the movement of the inertia member. At its rear end the firing member normally seats against the closure H and it may be lightly retained in such position by spring retainers M as shown in Figs. 1, 2 and 3 or by a centrifugally released locking member N as shown in Fig. 4.

A coil sprlng or rebound member O is mounted in the chamber in rear ofthe inertia member I which spring is normally expanded as shown in Fig. 1 but is adaptedto be compressed when the inertia mem-fl ber moves rearwardly as shown Fig'. 2.

'The inertia member normally rests against the front end of its chamber or the shoulder P at the front end of its chamber and its rearward movement is finally checked by the shoulder le? on the firing member.

.In-operation Vit may be assumed the parts `are normally in the position. shown in Fig.v

l and when the projectile is fired from the gun -the inertia of the member I will tend to resist its movement with the projectile resulting in a relative backward movement of said member to the position shown in Fig. 2. Before such relative movement can take place the resistance of the split ring must be overcome and when it has taken,

place the split ring locks the vinertia and firing members together. The movement will compress the rebound member and this` condition Will prevail during the time the projectile is accelerating but after the maximum acceleration and usually a short distanc'e beyond the muzzle of the gun the ref bound member asserts itself and drives the inertia member and the firing member ylocked thereto, forwardly to the position shown in Fig. v3 4when the lpoint strikes the ap or. detonator and fires t e same. Thereafter the action is similar to the action of the ordinary fuse now in use. Under some circumstances and for some uses it is desirable to' provide additional safety means such for example, as the centrifugally withdrawn lock N -which is thrown back against the tension of its spring by the spinning of the prlojectile due to the rifling of the gun barre To further protect the cap or detonator diaphragms such as at R, R of thin easily perforated material may be interposed between the firing mem'ber and caps.

It will be noted that the fuse is of simple:

construction, the parts being of such form that they may be manufactured and assembled with the greatest facility. When assembled no ne of the parts are under tension andV consequently deterioration cannot render the devic-e unsafe or cause a movement which will accidentally arm the fuse. The arming movements can only be effected by the discharge of the projectile from the gun and the actual firing of the ca only takes place after the of the gun. y

From the foregoing it will be seen that the inertia member normally stands at the forward extreme of its movement and the firing member is Yin such position that the cap or detonator is spaced from the firing pin but when the inertia member is moved to the rear and coupled to the firing member the relation of the two members is so changed that when the inertia member moves to the forward extreme of its movement the firing member will advance with it and the cap or detonator will be brought into engagement with the firing pin and fired. The retainers M perform a secondary function in that they exert a tendency to hold the parts in armed position until the other forces tending to hold the parts in this position are overbalanced when they releasel and the inertia member and firing member will advance with a jump or quick movement. Such devices are not essential but add to the efficiency of the fuse.

What I claim is:

l. A fuse embodying a forwardly movable firing member, a rearwardly movable inertia member, a resilient rebound member for resisting the rearward movement of the' inertia member independently of the firing member, means for coupling the firing member and inertia members together for simultaneous forward movement under the influence of the rebound member whereby the fuse will be armed during acceleration of the projectile and fired after maximum accel 'eration has been attained.

2. A fuse embodying a rearwardly movable inertia member, a resilient rebound member for normally holding the inertia member at the forward extreme of its movement independently of the firing member andreturnmg the same to such position after rearprojectile has le t the muzzle ward movement due to its .inertia and' aY firing member normally held in unarmed position and connections where-by the firing member will be advanced by the inertia member during its rebound or forward movement to iire the detonator.

`3. A fuse embodying a rearwardly movable inertia member, a resilient rebound member for normally holding the inertia member at the forward eXtreme of its movement independently of the firing member and returning the same to such position after rearward Vmovement due to its inertia and a firing member movable with relation to the inertia member lfrom an unarmed into an' armed position and connections whereby the firing member is carried forwardly by the inertia memberduring the rebound movement of the latter and with the firing member in its armed position with relation to the inertia member to lire the detonator.

4. A fuse of the character specified in claim 3 embodying releasable means for locking the inertia and firing members in 'unarmed relation, and means for locking said parts in their armed relation.

5. A fuse of the characterspecified in claim 3 embodying a yielding lock for retaining the inertia and -firing members in either armed or unarmed relation to each other, I

6. A fuse of the character specified in claim 3 embodying an inertia member having an axial opening and a firing member mounted in said opening and means for holding the firing member against a rearward movement with relation to the inertia member and permitting said members to move forwardly in unison.

7. A fuse of the character specied in ,claim 3 embodying means for temporarily restraining the forward movement of the inl ertia and tiring members to cause sudden acceleration of such movement.

-8. In a fuse the combination with a fuse body having a' central borev forming front and rear chambers with a shoulder at the forward end of the rear chamber, of a cap or detonator member fixed in the front chamber and facing rearwardly an inertia member movably mounted in the rear chamber, a resilient rebound member normally holding the inertia member forwardly against the said shoulder, a forwardly movable firing member mounted in the rear chambena 'and means for coupling the inertia and ring members for simultaneous forward movement during the rebound or forward vmove- ,ment of theinertia member.

EMIL GATHMANN. 

